C#去掉HTML标记

public string RemoveHTMLTags(string htmlStream)
{
if (htmlStream == null)
{
throw new Exception("Your input html stream is null!");
return null;
}
/*
* 最好把所有的特殊HTML标记都找出来，然后把与其相对应的Unicode字符一起影射到Hash表内，最后一起都替换掉
*/
//先单独测试,成功后,再把所有模式合并
//注:这两个必须单独处理
//去掉嵌套了HTML标记的JavaScript:(<script)[\\s\\S]*(</script>)
//去掉css标记:(<style)[\\s\\S]*(</style>)
//去掉css标记:\\..*\\{[\\s\\S]*\\}
htmlStream = Regex.Replace(htmlStream, "(<script)[\\s\\S]*?(</script>)|(<style)[\\s\\S]*?(</style>)", " ", RegexOptions.IgnoreCase);
//htmlStream = RemoveTag(htmlStream, "script");
//htmlStream = RemoveTag(htmlStream, "style");
//去掉普通HTML标记:<[^>]+>
//替换空格: |&|­| |­
htmlStream = Regex.Replace(htmlStream, "<[^>]+>| |&|­| |­|•|<|>", " ", RegexOptions.IgnoreCase);
//htmlStream = RemoveTag(htmlStream);
//替换左尖括号
//htmlStream = Regex.Replace(htmlStream, "<", "<");
//替换右尖括号
//htmlStream = Regex.Replace(htmlStream, ">", ">");
//替换空行
//htmlStream = Regex.Replace(htmlStream, "[\n|\r|\t]", " ");//[\n|\r][\t*| *]*[\n|\r]
htmlStream = Regex.Replace(htmlStream, "(\r\n[\r|\n|\t| ]*\r\n)|(\n[\r|\n|\t| ]*\n)", "\r\n");
htmlStream = Regex.Replace(htmlStream, "[\t| ]{1,}", " ");
return htmlStream.Trim();
}